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(No Model.) I 3 Sheets-Sheet 1.

I. 1). SMEAD. WARM AIR FURNACE.

N0.-599,0Z2. Patented Feb. 15, 18-98.

No Model.) 3 SheetsSheet2v In D. SMEAD. WARM AIR, FURNACE.

No: 599,022. Patented Feb. 15 1898.

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(No. Model.) 3 Sheets-Sheet 3.

I. D. SMEAD. WARM AIR FURNACE.

' N0n.599,022. Patented Feb. 15,1898.

UNITED STATES PATENT OFFICE.

ISAAC D. SMEAD, OF TOLEDO, OHIO, ASSIGNOR TO THE SMEAD FURNACE ANDFOUNDRY COMPANY, OF SAME PLACE.

WARlVl-AIR FURNACE.

SPECIFICATION forming part of Letters Patent No. 599,022, dated February1 5, 1898. Application filed June 28, 1897- Serial No. 642,706. (Nomodel.)

To all whom it may concern:

Be it known that I, ISAAC D. 'SMEAD, a citizen of the United States,residing at Toledo,

in the county of Lucas and State of Ohio, have My invention relates tofurnaces of that class used for heating large buildings-such asschool-houses, churches, court-houses, and

- the like; and the invention consists in constructing the body of thefurnace of plates having both interior and exterior heat-con-.

ducting flanges, in so constructing and arranging the interior flangesas to form a se-' ries of vertical flues for the heat and smoke,

in providing a smoke-flue along the top of the body and connecting thesame with the vertical flues and the fire-chamber by anarrow opening orthroat, and in a peculiar construction of the grate whereby the fire ismade to burn at the sides of the fire-box, and in cer-' tain otherdetails, all as hereinafter set forth.

Figure 1 is a perspective view of the furnace, looking from the rear andhaving one side broken away to show the interior. Fig. 2 is a transversevertical section on the line as w of Fig. 3. Fig. 3 is a side elevation,and

Fig. 4 a transverse section on the line y y of The object of thisinvention is to produce a furnace which shall more eflectually conveythe heat produced by the consumption'of the fuel to the exterior andthereby more effectually utilize the fuel consumed.

To construct a furnace on my plan, I form the body of a series'of platesA of the form shown in Fig. 2, and which plates have very wide flanges.B projecting from their exterior bottom of the walls of the fire-box,while the interior flanges O extend from the throat of the smoke-fluedown about two-thirdsor three-fourths of the way to a point where theside walls A begin to incline outward, as

shown inFig. 2.

The side plates A are curved inward to form an arched top to thefire-box, but instead of meeting at the center of the top they are soformed as to leave a narrow space or throat I at that point, and abovewhich they are curved in a semicircular form, so that when the platesforming the walls of the two sides of the fire-box are placed inposition and united the two semicircular portions at the top form acontinuous circular smoke-flue G,

bolted together, as shown in Figs. 3 and 4E,

and they'are also provided with a longitudinal flange a at the top forthe same purpose, as shown in Figs. 1, 2, and 3.

The plates A, which form the side walls of the furnace, are inclinedoutward from a point some distance above the point where the side gratesrest against them to the termination of said plates below'the grate, asshown in Fig. 2. tion is that the ashes tend to fall away from the sidesinstead of banking'up against the side walls, as is' usually the case,and a free open space is left below the side grates, through which theashes fall and through which the air passes at the sides, where thecombustion takes place. By this construction and the use of the inclinedside grates the latter are rendered practically self-cleaning, therebyaffording greater facility for the entrance of the air close to the sidewalls,where it is desired to produce the greatest heat.

Atthe rear of the furnace-body proper I locate two radiating drums D,each composed of two cast-iron sections united at their centerexternally by flanges and bolts, as shown clearly in Figs. land 3. thesedrums is provided with a large central opening R, toward which thebottom wall inclines at the sides, as shown in Fig. 1, so that Theresult of this construc- The bottom wall of Ice the soot and ashes whichenter these drums will find a ready exit at the bottom. Underneath thesedrums and connected thereto by collars or tubes 0, I locate alongitudinal receptacle J, the rear end of which is extended far enoughto project through the wall of the furnace, as shown in Fig. 3, fromwhich the accumulation of soot and ashes can be removed wheneverdesired, it being provided with a door N at its outer end for closingthe same. At the top these drums are connected to the smokeflue G by asuitable collar and to each other by collars and a short section ofpipe, while near their bottom they are connected bytwo short pipes L, asshown in Fig. 1.

In the pipe which connects the drums at the top is secured a valve ordamper T to be operated by a rod R, extending to the front of thefurnace, so that when the damper is turned to a horizontal position itopens the direct draft through the top of the drums, but when closed thecurrent passes downward in the first drum and from thence upward throughthe second drum and thence out through the smoke-pipe at the rear.

In order to cause the fuel to burn at the sides only, I make the gratein two separate sections with a dead-plate P between them, as shown inFigs. 1 and 2. Each section of the grate is composed of two parts, theone part E consisting of a series of bars which are arranged in ahorizontal plane with their upper surface on a level with the dead-plateP, as clearly shown in Fig. 2, while the other section F is set inclinedat an angle of about forty-five degrees,m ore or less,a-s is also shownin Fig. 2. These grate-bars and the deadplate extend from front to rearof the fire-box or body of the furnace, as shown in Fig. 1, though it isnot absolutely necessary that they extend the entire length, but Iprefer to so make them.

\Vhile I prefer to use the inclined side grates F, as they tend to throwthe ashes away from the side walls and admit air at a higher point atthe sides, it is obvious that the flat grates may be extended outward tothe side walls and the inclined grates be thereby dispensed with andstill keep the fire at the sides in close contact with the sidewalls,the operation being similar in principle or effect and differing only indegree. I,however,consider the use of the inclined grates as preferablefor the reasons stated.

For the purpose of admitting more air at or near the rear end to minglewith and more ellectually consume the gases I prefer to make thedead-plate P with perforations in its rear portion, as represented inFig. 1, though it may be made imperforate, if preferred. Whether theperforated or imperforate dead-plate be used will depend upon the kindof coal or fuel that is to be be used in the furnace. The result of thisconstruction is that the fire is produced in two sheets, one along eachside, and the flame and smoke arising therefrom instead of passingbackward along the center of the fire-chamber, as in ordinarybox-furnaces, passes upward in the fines formed by the interior flangesO to the throat I at the top, as indicated by the arrows in Fig. 2, andthence into and through the smoke-flue G to the drums at the rear.

By the arrangement of the wide dead-plate at the'centerand the narrowgrates at the sides it will be seen that the air to support combustionis delivered at each side in the form of a sheet extending from front torear and that consequently the combustion of the fuel occurs at thesides and at the base of the vertical flues formed by theinwardly-projecting flanges, the products of combustion passing directlyupward in these flues, through the throat I, and into the smoke-pipe Gand thence backward through the drums D D. The fuel on the dead-plate atthe center does not burn, but is coked by the heat of the burning fuelat the sides, the gases given off by the coking of the same minglingwith the heat and air at the sides and being thereby thoroughlyconsumed. When it becomes necessary to replenish the fuel, the mass ofcokedfuel on the dead-plate is broken up and shoved over onto the gratesat the sides, after which fresh coal is again piled up on the dead-plateto go through the coking process, and thus there is a continuous processof first coking the fresh coal and then burning the fuel that has beencoked, and which gives far better results than the ordinary method ofburning the fresh fuel on a grate extending across the entire chamber.By this means the heat is brought more effectually into contact with theside walls and the interior flanges C, which conduct it directly to theouter flanges B. It will be seen, therefore, that not only are the sidewalls more efiectuallyheated, and consequently radiate more heat, butthat the outer flanges B are also moreeffectually heated, and theseflanges, being of unusual extent and width, add immensely to the extentof the heat-1a diating surface.

In setting these furnaces they are inclosed with brick walls, asrepresented in Fig. and by placing a plate I) at each side near the top,as there shown, it will be seen that the air which enters at anysuitable or convenient point at the bottom (usually through a series ofopenings in the brick wall along the whole length of one side) iscompelled to pass upward between the flanges B, as indicated by thearrows in Fig. 2, and is thus distributed equally the entire length ofthe furnace and on both sides.

As the body is composed of a series of plates of uniform shape and size,it will be seen that the fire-box may be made longer or shorter, andthus the size of the furnace be varied at will to suit different-sizedbuildings. They are composed wholly of cast-iron, and as the largestsize weighs about seven thousand pounds it will be seen that with thispeculiar construction their heating capacity is very great. Experimenthas demonstrated that they are far superior in that respect to thefurnaces heretofore patented and used by me.

Having thus fully described my invention, what I claim is I 1. Afurnace-body provided with a longitudinal heat and smoke flue along itstop, said flue communicating with the fire box or chamber by a narrowopening or slot, substantially as shown and described.

2. The combination in a furnace, of the side walls provided withinwardly-projecting vertical flanges O and the longitudinal flue G atthe top communicating with the fire box or chamber by a narrow openingor slot, all arranged to operate'substantially as and for the purposeset forth.

3. A furnace-body composed of a series of sections, each provided withone or more internal vertical flanges 0, one or more external verticalflanges B, and terminating at the top in a semicircular plate of thefull width of the segment, substantially as shown and described. 4. Thecombination in a furnace, of a central dead-plate, and a grate at eachside thereof, with a fire-box having the lower portion of its wallsadjoining the grates inclined outward and downward substantially asshown and described, whereby the ashes are caused to fall away from theinclined side walls, and

an unobstructed space for the passage of the air is left at the sides,as set forth.

5. The combination in a furnace, of a firebox provided at its sides witha series of vertical flues formed by inwardly projecting flanges, saidfines communicating at their upper end-with a horizontal heat and smokeflue G, and a separate narrow grate along each side below said internalflues with a dead-plate between said grates substantially as shown,whereby the fire is confined to the sides and the products of combustionare caused to pass directly upward through said flues and into thehorizontal flue at the top, as set forth.

6. In combination, the elongated furnaceflue G communicating with saidbody, the vertical drums D, D, connected to said body by an extension ofthe flue G and to each other by pipes L, and a horizontaldust-receptacle J beneath said drums and communicating therewith, with adoor at its outer end, all construct-ed and arranged substantially asshown and described.

In witness whereof I hereunto set my hand in the presence of twowitnesses.

ISAAC D. SMEAD. Witnesses: L. A. WILLOUGHBY,

ANTHONY KUEFER.

